1. Field of the Invention
The present invention relates to a patient detecting apparatus which detects that a patient is present on a bed and particularly to such a patient detecting apparatus which can detect a position on a bed where a patient is present.
2. Related Art Statement
If an inpatient who is sleeping on a bed accidentally falls off the bed, the patient may be injured. However, if the patient cannot move without help, the patient cannot inform a doctor or a nurse of his or her injury, so that treatment of the injury may be delayed. To avoid this, there has conventionally been used a patient detecting apparatus which detects whether a patient is present on a bed. In addition, the patient detecting apparatus may be used to detect whether a poriomaniac patient is absent from a bed.
The conventional patient detecting apparatus includes a pressure detecting device which is placed on a particular portion of a bed on which a patient sleeps and, when the pressure detecting device detects a pressure higher than a predetermined value, the patient detecting apparatus judges that the patient is present on the bed.
However, the conventional patient detecting apparatus can only judge whether a patient is present on a bed but cannot prevent the patient from falling off the bed.
It is therefore an object of the present invention to provide a patient detecting apparatus which can detect a position on a bed where a patient is present, in particular, a position where the patient is likely to fall off the bed.
The above object has been achieved by the present invention. According to a first feature of the present invention, there is provided an apparatus for detecting a patient, comprising a plurality of pressure detecting devices which are adapted to be placed on a bed such that the pressure detecting devices are arranged in a widthwise direction of the bed, and which detect respective pressures and produces respective pressure signals representing the detected pressures; and a position detecting means for detecting, based on the pressure signals supplied from the pressure detecting devices, a position, in the widthwise direction of the bed, where the patient is present.
According to this feature, the plurality of pressure detecting devices are placed on the bed such that the pressure detecting devices are arranged in a widthwise direction of the bed, and produce respective pressure signals representing respective detected pressures. Thus, the plurality of pressure signals are obtained in the widthwise direction of the bed. And, the position detecting means detects, based on those pressure signals supplied from the pressure detecting devices, a position, in the widthwise direction of the bed, where the patient is present. Thus, the present apparatus can judge whether the patient is present at a dangerous position where the patient is likely to fall off the bed.
According to a second feature of the present invention, the pressure detecting devices comprise respective bags each of which is filled with a fluid, and the apparatus further comprises a fluid-amount control means for controlling an amount of the fluid present in each of the respective bags of the pressure detecting devices, the fluid-amount control means comprising changing means for identifying a first bag of the respective bags that supports a greatest portion of a total weight of the patient, and changing the respective amounts of the fluid present in the respective bags of two or more pressure detecting devices so that a second bag of the respective bags that is different from the first bag supports a greatest portion of the total weight of the patient.
The bags as the pressure detecting devices are provided at such positions where the bags can always contact the patient so as to detect the position of the patient. Thus, a portion of the patient that is pressed by the bag or bags is likely to suffer bedsores. This problem can be effectively solved according to this feature. That is, the changing means identifies a first bag that supports a greatest portion of a total weight of the patient, and changes the respective amounts of the fluid present in the respective bags of two or more pressure detecting devices so that a second bag different from the first bag supports a greatest portion of the total weight of the patient. Thus, the present apparatus can effectively prevent the patient from suffering bedsores.
According to a third feature of the present invention, the pressure detecting devices comprise respective bags each of which is filled with an air and includes a contact portion that is adapted to contact the patient and is formed of a porous sheet, the porous sheet allowing the air to permeate therethrough into an outside space, and wherein the apparatus further comprises an air pump which supplies the air to said each of the respective bags.
According to this feature, when the air pump supplies the air to each of the bags, the air leaks, little by little, through the porous sheet providing the contact portion of the each bag that contacts the patient. Thus, the present apparatus can effectively prevent portions of the patient that contact the bags, from perspiring on the bags.